1. Field of the Invention
The present invention relates to novel methods for processing a digitally exposed photographic translucent or transparent material. The present invention can provide a translucent or transparent material having an increased visual maximum density, and is particularly suitable for use in large format development processes.
2. Description of the Related Art
The processing of a color photographic material generally includes a color development step as the primary step for producing an image. In the color development step, silver halide exposed to light is reduced with a color developing agent to produce silver. At the same time, the oxidized color developing agent is reacted with a color former (i.e., a coupler) to form a dye image. In a subsequent desilvering step, the silver produced in the color development step is oxidized with an oxidizing agent (i.e., a bleaching agent) and then dissolved by a silver ion complexing agent (i.e., a fixing agent) to thereby provide a dye image only on the color light-sensitive material.
Both analog and digital exposure methods can be used to expose large format photographic material. An analog exposure method typically employs, for example, a tungsten lamp. Typical operation conditions of such a tungsten lamp include an exposure time of about 0.5 second and an intensity about 600 lux. A digital exposure method typically uses a digital writer to expose a photographic material. The use of such digital exposure method can provide various benefits such as, for example, enabling the use of an image stored in digital format directly with the exposure device. This can obviate the need to use an enlarger device, as is typically required in large format analog exposure methods. In addition, the use of a digital exposure method enables the images to be easily altered using any one of a number of commercially available computer programs.
One type of photographic material that can be used in digital processing is a transparent or translucent material which enables the material to be used, for example, for display purposes. Such transparent or translucent material is particularly useful in applications where the material is used in conjunction with backlighting. For example, a light source can be placed behind the transparent or translucent material and the light can pass through the material, thereby illuminating the material.
A digital exposure method is typically used in exposing such transparent or translucent material. However, the digital exposure method typically entails a higher intensity and a shorter time of exposure in comparison with conventional analog exposure (e.g., with a conventional tungsten lamp light source). The visual maximum density of the image produced on the digitally exposed transparent or translucent material is typically lower when the same material and processing conditions are applied. While not being bound by any particular theory, it is believed that this reduced density may be due to the formation of several sub-latent images which results in a less developed latent image. Thus, there exists a need to increase the visual maximum density of a transparent or translucent photographic material, preferably by relatively inexpensive means.
One attempt to address this problem is to increase the exposure time of the transparent or translucent material. However, this typically lowers the lifetime of the exposing device, with replacement costs of such device typically being relatively high. In addition, increasing the exposure time can lead to an increased stain of the materials to an undesirable degree.
Increasing the development time of the photographic material has also been proposed to address the problem of low visual density in transparent or translucent materials. However, this offsets one advantage of using digital exposure methods, i.e., providing a decreased exposure time. In addition, an increased development time can result in undesirable photographic effects, such as increased stain densities in the unexposed portions of the photographic material, which can lead to poor image quality.
Advantageously, the present invention can conspicuously ameliorate or overcome the above-described problem of low visual maximum densities obtained from the digital exposure of transparent or translucent material. For example, the inventive methods can provide improved processing of color images on transparent or translucent materials with higher optical maximum densities. The methods are particularly applicable in preparing materials for use in backlit applications. Further, the inventive methods can provide high quality photographic images using digital exposure methods without any need for employing impractically long exposure or development times.
Other objects and aspects of the present invention will become apparent to one of ordinary skill in the art upon review of the specification and claims appended hereto.